How would I go about about making wraparound glasses?
I think I'm not that an expert. But if you can look up if this helps:
1. Take a cube.
2. Subdivide it or put a subsurf modifier.
3. Put a cast modifier.
4. Apply those.
5. Cut the sphere using  the frame of the sun-glass frame with boolean modifier.
                 .................hope this helps...............
P.S. remember to adjust the radius so that the glass doesn't look too bulky..